Electrical contact means



March 10,1942. e. E. WHiTEHEAD 2,276,130

ELECTRICAL CONTACT MEANS Filed May 10, 1941- 2 Sheets-Sheet l y F/G. 2W

March 10, 1942. W'HlTEHEAD 2,276,130

ELECTRICAL CONTACT MEANS Filed May 10, 1941 2 Sheets-Sheet 2 A /aa )Wl QVTWE Patented Mar. 10, 1942 UNlTED STATES PATENT OFFICE Application May 10,

In Great Britain 12 Claims.

This invention relates to contacts for electric circuit breakers, switches, current carrying connectors and the like, and has particular reference to devices such as that described in prior British specification No. 409,085, in which one contact element is constituted by a plurality of flexible laminae whose edges make line contact with the complementary contact element.

The invention comprises the arrangement in which the contact element which is constituted by a plurality of flexible laminae is a butt contact element.

The invention further comprises the arrangement that the laminae are of helical form.

In order that the invention may be the more clearly understood a switch in accordance therewith will now be described, reference being made to the accompanying drawings wherein- Figure 1 is a sectional side elevation of said switch in the closed position.

Figure 2 is a plan of the laminated contact element.

January 25, 1940 Figure 3 is a plan illustrating one of thelaminations of said laminated contact element in course of formation.

Figure 4 is a side elevation of the same.

Figure 5 is a fragmentary view of the upper extremities of three of the contacting laminations of said laminated contact element together with the stiffening and spacing laminae between them.

Figures 6, '7, 8 and 9 are similar views to Figure 5 illustrating alternative forms of stiffening and spacing laminae; and

Figure 10 is a detail view showing a pair of the helical contacting laminae in spaced condition and an intermediate helical spacing lamina, the ends of the spacing lamina being illustrated as similar to that shown in Figure 8.

Referring to Figures 1 and 2, the movable switch element comprises a main moving contact I of roughly cylindrical form and an auxiliary moving contact 2 extending axially from said main moving contact in the forward direction; and the stationary switch element comprises a main stationary contact 3 in the form of an annulus against one face of which the main moving contact l is adapted to abut, as shown in Figure 1, after the auxiliary moving contact 2 has passed through it, while the auxiliary stationary contact l takes the form of a suitable spring loaded contact at the rear of the main stationary contact, with which said auxiliary moving contact engages.

The parts are so arranged that, when the movable switch element is moved into and out of engagement with the stationary switch element, the auxiliary moving contact 2 engages the auxiliary stationary contact l before the main moving contact I engages the main stationary contact3,

and disengages said auxiliary stationary contact after said main moving contact has disengaged said main stationary contact.

In the present arrangement the main moving contact I is constituted by a. multiplicity of laminae la arranged around a central support 5 whose axis is in the line of movement. Each of these laminae la is in the form of a helix (that is the form of a screw thread) with its plane transverse to the axis of the helix, the extent of the helix being rather less than one turn and the extremities laa being bent outwardly parallel to the axis of the helix. These laminae la are threaded on to the central support 5 one above the other so that their lower or rear ends.

laa rest on a shoulder 6 extending outwardly from said central support. It will be seen that, to make this possible, the laminae la have to be angularly spaced from one another around said central support 5.

It will be seen that the upper or forward extremities laa of the laminae la lie on the surface of a flat disc. It is these upper or forward extremities which constitute the contacting surface of said main moving contact and engage, as shown, against the flat face of the annulus 3 forming the main stationary contact.

It will be appreciated that the extremities laa,

of each lamina la will make independent line contact both with said main stationary contact 3 and with the shoulder B on the central support 5 and that each will yield resiliently and independently so that good contact is ensured between the laminae la as a whole and both said main stationary contact 3 and said shoulder 6. The latter contact establishes electrical connection between the laminae and the terminal for the moving switch element.

If said moving switch element is arranged in an upright position, the laminae la may rest freely by gravity on the aforesaid shoulder 6.

Interleaved alternately with these operative or contacting laminae la are stiffening and spacing laminae lb. These stiffening and spacing laminae lb have their bent over extremities lbb made short so as not to extend quite to the shoulder 6 and to the main stationary contact 3 respectively. The length of said stiffening and spacing laminae lb in a circumferential sense is however slightly greater than that of the contacting laminae la and thus said stiffening and spacing laminae act to space the contacting laminae in a circumferential sense, maintaining a constant space between each adjacent pair of bent over ends laa. This will be understood if it is observed that the upper end of each stiffening and spacing lamina abuts the upwardly bent end laa of the contacting laminae immediately below it while the lower end of the same stilfenmg and spacing lamina abuts-the'downwardly contact.

bent end laa of the contacting lamina immediately below it. Thus the bent over ends laa of each two adjacent laminae la are held apart by the action of the whole length of the stiffening and spacing lamina lb between them. In addition to this the stiffening and spacing laminae lb are so formed, as to exert separating pressure on the contacting laminae la between which they lie. Thus each stiffening and spacing lamina lb is so formed that, at or near its lower or rear end it presses against the contacting lamina la beneath it and at or near its upper end it presses against the contacting lamina la above it. Thus said contacting laminae are also spaced in an axial sense and added resiliency is given to the The contacting laminae la may suitably be of copper and the stiffening and spacing laminae of phosphor bronze.

The outer diameter of the stifiening and spacing laminae lb may be less than that of the contacting laminae la as indicated in Figure 2.

Each lamina la is formed from a blank as illustrated in Figures 3 and 4. The extremities laa are bent on opposite sides of the blank not quite to the normal as clearly shown in these figures and when the blank is then given its helical form said extremities will become parallel to the axis as heretofore stated. The stiffening and spacing laminae lb will be made in exactly the same way.

Referring now to Figures 6 to 9, these show way as those illustrated In Figures 7, 8 and 9,

in Figures 2 and 5. however, the laminae lb are formed with portions lying directly between portion lbb lying between adjacent pairs of bent over ends laa. Finally in Figure 9 said laminae lb are formed with a ridge lbb near their ends so that adjacent pairs of bent over ends laa abut respectively against the extremity of the lamina lb between them and the ridge lbb of said lamina lb, so that, as before, they are firmly spaced.

It is to be understood that, in each of the Figures to 9, the lower ends of the laminae la, lb, will be identical with the upper but reversed, that is to say at the lower ends the laminae lb will press downwardly against the laminae la beneath them.

The auxiliary contacts 2 and 4 may take any suitable formfor example any of the forms described in the provisional specification of our co-pending British application No. 1527/40 of even date herewith would be suitable.

In the particular arrangement illustrated the auxiliary contact 2 takes the form of an axial ery of said contact 2.

Openings 9* are provided for freely admitting the surrounding air or oil to the contacting region of the auxiliary contacts.

What I claim and desire to secure by Letters Patent is:

l. A butt contact for an electric circuit breaker or the like, comprising a plurality of flexible laminae, each in the form of a helix with its plane transverse to its axis, said conare formed which mentary butt contact.

5. A butt contact for an electric circuit breaker or the like, comprising a plurality of flexible 6. A butt contact for an electric circuit breaker or the like, comprising a plurality of flexible contacting laminae, each in the form of a helix with its plane transverse to its axis, said contacting laminae being stacked together, and successively angularly spaced around their common axis, and each having both its ends bent outwardly, a supporting base with which the ends of said contacting laminae at one end make edge contact, the ends of said contacting laminae at the other end being adapted to make edge contact with a complementary butt contact, and stiffening and spacing laminae interleaved alternately with said contacting laminae and operating to space said outwardly bent ends of said contacting laminae at both ends.

'7. A butt contact for an electric circuit breaker or the like, comprising a plurality of flexible contacting laminae, each in the form of a helix with its plane transverse to its axis, said contacting laminae being stacked together, and successively angularly spaced around their common axis, and each having both its ends bent outwardly, a supporting base with which the ends of said contacting laminae at one end make edge contact, the ends of said contacting laminae at the other end being adapted to make edge contact with a complementary butt contact, and stiffening and spacing laminae interleaved alternately with said contacting laminae, said stifiening and spacing laminae being of the same general helical form as, but of slightly greater circumferential extent than, said contacting laminae sothat their ends abut against the remote outwardly bent ends of adjacent contacting laminae and thereby space said outwardly bent ends of said contacting laminae at both ends.

8. A butt contact for an electric circuit breaker or the like, comprising a plurality of flexible contacting laminae, each in the form of a helix with its plane transverse to its axis, said contacting laminae being stacked together, and successively angularly spaced around their COIIlIIlOIl axis, and each having both its ends bent outwardly, a supporting base with which the ends of said contacting laminae at one end make edge contact, the ends of said contacting laminae at the other end being adapted to make edge contact with a complementary butt contact, and stiffening and spacing laminae interleaved alternately with said contacting laminae, said stiffening and spacing laminae being of the same general helical form as said contacting laminae, and being formed at both ends with spacing portions which lie directly between outwardly bent ends of adjacent contacting laminae to thereby space said out wardly bent ends.

9. A butt contact for an electric circuit breaker or the like, comprising a plurality of flexible contacting laminae, each in the form of a helix with its plane transverse to its axis, said contacting laminae being stacked together, and successively angularly spaced around their common axis, and having their ends bent outwardly whereby edges are formed which make contact with a complementary butt contact, and stiffening and spacing laminae interleaved alternately with said contacting laminae and formed so as to exert a resilient separating pressure on the contacting laminae between which they lie and to space said outwardly bent ends of said contacting laminae.

10. A butt contact for an electric circuit breaker or the like, comprising a plurality of flexible contacting laminae, each in the form of a helix with its plane transverse toits axis, said contacting laminae being stacked together, and successively angularly spaced around their common axis, and each having both its ends bent outwardly, a supporting base with which the ends of said contacting laminae at one end make edge contact, the ends of said contacting laminae at the other end being adapted to make edge contact with a complementary butt contact, and stiffening and spacing laminae interleaved alternatively with said contacting laminae, said stiffening and placing laminae being of the same general helical form as, but of slightly greater circumferential extent than, said contacting laminae so that their ends abut against the remote outwardly bent ends of adjacent contacting laminae and thereby space said outwardly bent ends of said contacting laminae at both ends, and said stiffening and spacing laminae being formed so as to exert a resilient separating pressure on the contacting laminae between which they lie.

11. A butt contact for an electric circuit breaker or the like, comprising a plurality of flexible contacting laminae, each in the form of a helix with its plane transverse to its axis, said contacting laminae being stacked together, and successively angularly spaced around their common axis, and each having both its ends bent outwardly, a supporting base with which the ends of said contacting laminae at one end make edge contact, the ends of said contacting laminae at the other end being adapted to make edge contact with a complementary butt contact, and stiffening and spacing laminae interleaved alternately with said contacting laminae, said stillening and spacing laminae being of the same general helical form as said contacting laminae, and being formed at both ends with spacing portions which lie directly between outwardly bent ends of adjacent contacting laminae to thereby space said outwardly bent ends, and said stiffening and spacing laminae being also formed so as to exert a resilient separating pressure on the contacting laminae between which they lie.

12. An electric circuit breaker or the like comprising a laminated butt contact, a complementary butt contact, and auxiliary contacts which make contact before, and break contact after, said butt contacts, said laminated butt contact comprising a plurality of flexible contacting laminae, each in the form of a helix with its plane transverse to its axis, said contacting laminae being stacked together and successively angularly spaced around their common axis and each having both its ends bent outwardly, and a supporting base including a surface with a post projecting outwardly therefrom, said contacting laminae being arranged around said post with their ends at one end making edge contact with said surface, the ends of said contacting laminae at the other end being adapted to make edge contact with said complementary butt contact, said complementary butt contact taking the form of an annulus and one of said auxiliary contacts being formed on a continuation of said post and being adapted to extend through said annulus to engage the other auxiliary contact.

GEORGE ETHELBERT WHITEHEAD. 

